Furnace and cooling control therefor

ABSTRACT

A furnace cooling control apparatus provided by a plurality of water-cooled panels supported within a furnace above a conveyor used to transport heated workpieces along the furnace hearth. The panels are arranged in an edge-to-edge relationship along the length of the furnace with pairs of panels arranged end-to-end across the width of the furnace. A drive connected to a centrally-located shaft on each panel independently, or if required a group of panels, rotates the panels to expose a portion or the entire area of either an insulated face on one side of the panel for slow cooling or a water-cooled face on the other side of the panel for fast cooling. A temperature control system is connected to the drive for adjusting each panel or a group of panels position to maintain a desired cooling rate of the workpieces.

u 3,801,265 [451 Apr. 2, 1974 United States Patent [1 1 Bricmont [57] ABSTRACT A furnace cooling control apparatus provided by a plurality of water-cooled panels supported within a furnace above a conveyor used to transport heated FURNACE AND COOLING CONTROL THEREFOR [75] Inventor: Francis H. Bricmont, Pittsburgh, Pa.

[73] Assignee: Bricmont & Associates, lnc.,

Pittsburgh paworkpieces along the furnace hearth. The panels are arranged in an edge-to-edge relationship along the length of the furnace with pairs of panels arranged end-to-end across the width of the furnace. A drive [22] Filed: Dec. 6, 1972 [211 3l248l connected to a centrally-located shaft on each panel independently, or if required a group of panels, rotates the panels to expose a portion or the entire area of either an insulated face on one side of the panel for slow cooling or a water-cooled face on the other side of the panel for fast cooling. A temperature control system is connected to the drive for adjusting each panel or a [52] U.S. [51] Int. [58] Field of Search..........................

[56] References Cited UNITED STATES PATENTS group of panels position to maintain a desired cooling rate of the workpieces.

3,104,442 9/1963 Cremer et 432/27 X 3,618,914 6/1970 432/42 8 Claims, 3 Drawing Figures 0r Firm-Brown, Murray, Flick &

FURNACE AND COOLING CONTROL THEREFOR BACKGROUND OF THE INVENTION The present invention relates to a controlled cooling furnace for rapid air-quenching of heated workpieces such as employed for a controlled cooling process of ductile iron pipe. In place of open air cooling of certain types of workpieces such as ductile iron pipe, cooling furnaces have been provided with a system of air ducts in the roof of the furnace. Air circulated through the ducts provides a medium for withdrawing heat from the furnace due to radiation cooling of the workpieces. This form of cooling furnace has been found to be inefflcient and unacceptable for present-day requirements, particularly to meet the demands of a heat removal rate necessary to drastically cool such workpieces. The air duct system cannot be effectively controlled to provide a differential workpiece cooling as a function of time. Another aspect concerning the concept of differential cooling relates to different cooling rates along the length of a workpiece. Thus, for example, with respect to a ductile iron pipe, in order to effectively remove the greater quantity of heat from an enlarged bell-mouthed section at one end of the pipe requires a heat removal rate different from that of the rate for the remaining length of the pipe. Moreover, this furnace cooling arrangement lacks the capacity to remove the quantity of heat from within the furnace necessary to drastically air-quench a workpiece particularly large sectional areas from l800F-1275, for example, within 7-l0 minutes and then continue cooling at a lower rate down to an ambient temperature or other desired temperature before discharging the workpiece from the furnace.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a workpiece cooling furnace incorporating panels which are fluid-cooled on'one side and insulated on the other side and which are adjustably arranged above and/or below hot workpieces within the furnace.

It is a further object of the present invention to provide an improved workpiece cooling furnace operative to cool a workpiece by radiation to a fluid cooled surface which is adjustably arranged within the furnace for controlling the cooling rate of the workpiece.

It is a still further object of the present invention to provide a control system for adjustably positioning fluid cooled panels supported within a furnace above and/or below heated workpieces for cooling by radiation to the surface of the panel.

According to the present invention, there is provided a cooling furnace and control therefor comprising a furnace hearth and conveying means for transferring a workpiece through the furnace, a plurality of panels arranged above and/or below the conveying means within the furnace, each panel being rotatably supported for selectively adjusting the location of opposed surfaces on the panels.

In the preferred form of the invention, one of the aforesaid panel surfaces is fluid cooled and the other panel surface is insulated. An automatic control system incorporating a temperature measuring device for the workpiece is provided for controlling the position of the panel surfaces. The panels are preferably arranged in a side-by-side relationship along the length of the furnace and in an end-to-end relationship across the width thereof.

These features and advantages of the present invention as well as others will become more apparent to those skilled in the art when the following description is read in light of the accompanying drawings, in which:

FIG. 1 is an elevational view, in section, of a cooling furnace embodying the features of the present invention;

FIG. 2 is a sectional view taken along line lI-II of FIG. 1; and

FIG. 3 is a partial plan view taken along line llI--lll of FIG. 1.

With reference now to FIGS. 1 and 2 of the drawings, there is illustrated a cooling furnace 10 which includes side walls 11 supporting a roof 12 above a furnace hearth 13. The hearth 13 is formed with spaced-apart troughs containing conveyor chains 14 each provided with a plurality of dogs 15 for transferring heated workpieces through the furnace. According to the embodiment of the present invention illustrated in the drawings, the furnace hearth is inclined to the horizontal and pipe sections 16 are shown being conveyed along the furnace hearth by the dogs and conveyor chains. The sections of pipe 16, as illustrated in FIG. 1, have enlarged bell-mouthed ends 16A which define an increase in both diameter and mass of metal when compared to the remaining length of the pipe. To accommodate this shape of workpiece, the furnace hearth has a wide trough at one side extending along the length of the furnace. While the features of the present invention are particularly useful for the controlled cooling of ductile iron pipes, those skilled in the art will appreciate that other types and shapes of workpieces may be loaded into the furnace and cooled according to the features of the present invention without departing from the features and advantages thereof.

As shown in FIG. 1, rectangular-shaped cooling panface a mat-like layer of heat resistant, insulation material 22. This material may be selected from any one of a numerous products presently available in the industry and one such product is sold under the trade name of KAOWOOL. This product is an aluminum silicon fiber formed into a sheet or mat with a l4-pound density and operating temperature range of up to 2200F.

A system of fluid transfer ducts 23 forms a heat exchanger which is attached to the surface of the plate 21 opposite the insulation 22. These ducts are longitudinally arranged at spaced intervals across the width of the plate 21 and conduct a water-like coolant in opposite direction as indicated by the arrows in FIG. 3. The ends of the fluid ducts 23 are connected to a pipe 24 having a baffle plate 25 which divides the pipe into a water input channel 26A and a water discharge channel 268. A rotary fluid coupling 27 is mounted on the end of the pipe 24. Water or other liquid coolant passes from a stationary supply pipe 28 through the rotary fluid coupling 27 and into the channel 26A. The discharge channel 26B delivers the liquid from the panel ducts through the coupling 27 and into a stationary pipe 29'.

A trunnion shaft 31 extends from the end of the panel opposite the pipe'24 and coaxially therewith. Rotatably supporting each panel is a pillow block 32 for receiving the pipe 24' and arranged in the furnace wall 1 1. At the other end of the panel, the trunnion shaft 31 is received in a sleeve 33 which is carried by a depending plate 34 supported by the furnace roof. The plate 34 may, if desired, contain water coolant openings arranged in a convenient manner within the plate. The panels forming each cooling unit 19 are supported in a like manner by a sleeve 33 and pillow blocks 32 arranged in the opposed furnace walls. For each panel there is provided a worm wheel 35 secured on the pipe 24 between the coupling 27 and the furnace wall 11. The wheel 35 is driven by a pinion 36 secured to the shaft of a motor 37. The motor 37 is connected to a power supply 38 having a control 39 which receives a signal from the output line of a pyrometer 41 arranged within the furnace to measure the temperature of the pipe 16. Based on the actual temperature measurements'by the p'yrometer, the control 39 produces an error signal based on a desired cooling curve. This error signal is used to control the position of each panel. The wheel 35 could, also, be provided with a handle or crank for manual operation. If desired, these wheels could be driven andcontrolled in groups. The

7 wheel 35 can also be driven by a chain drive instead of the pinion 36.

-Water circulated through the heat exchange surface of the panel provides a cold surface, which, when exposed to the heated workpieces or pipes 16, provides relative position of the ducts 23 with respect to the insulation 22 of the panels forming each cooling unit 19 and from unit to unit.

While the features of the invention may be employed in numerous applications, highly desirable results will be obtained for the cooling of ductile iron pipes where according-to cooling rate graphs, a drastic air quench is to be carried out from, for example, an initial temperature of I800F to 1450F within ten minutes and even 7-8 minutes as desired. Following a temperature reduction to 1450F, the cooling rate is substantially reduced which can be readily accommodated by exposing an increased area of the insulated panel surface to the workpieces. l

Although the invention has been shown and described in connection with a certain specific embodiment, it will be readily apparent to those skilled in the art that various changes in form and arrangement of parts may be made to suit requirements without departing from the spirit and scope of the invention.

I claim as my invention:

l. A cooling control apparatus in combination with a furnace or the like having a hearth for supporting heated workpieces, said apparatus comprising:

aplurality of panels arranged from said hearth in a spaced-apart relationship thereto,

means for rotatably supporting said panels within said furnace,

fluid conduit means for cooling a surface on one side of said panels,

insulating means on the surface of the panel opposite said fluid cooled surface, and

drive means for rotatably positioning said panels within an arcuate path of travel to selectively expose said surfaces to said workpieces according to a desired cooling rate.

2. An apparatus according to claim 1 further comprising conveyor means for transferring heated workpieces continuously along said furnace hearth at a spaced relation from said panels.

3. An apparatus according to claim 2 wherein at least two of said panels are supported by said means for rotatably supporting in an edge-to-edge relationship along the length of the cooling furnace.

4. An apparatus according to claim 3 wherein a pair of said panels is supported by said means for rotatably supporting to extend in an end-toend relationship across the width of said cooling furnace.

5. An apparatus according to claim 4 wherein said means for rotatably supporting said panels includes a plate member projecting from the roof of said fumace for rotatably supporting adjacent ends of said panels while arranged in said end-to-end relationship.

6. An apparatus according to claim 1 further comprising temperature measuring means-for workpieces supported on said furnace hearth, and control means responsive to said temperature measuring means for energizing said drive means.

7. An apparatus according to claim 1 wherein said fluid coolant means includes longitudinal ducts arranged at spaced intervals across the width of each panel.

8. An apparatus according to claim 7 wherein said insulation means is further defined to include a fibrous mat of heat insulating material having a working temperature range up to 2200F. 

1. A cooling control apparatus in combination with a furnace or the like having a hearth for supporting heated workpieces, said apparatus comprising: a plurality of panels arranged from said hearth in a spacedapart relationship thereto, means for rotatably supporting said panels within said furnace, fluid conduit means for cooling a surface on one side of said panels, insulating means on the surface of the panel opposite said fluid cooled surface, and drive means for rotatably positioning said panels within an arcuate path of travel to selectively expose said surfaces to said workpieces according to a desired cooling rate.
 2. An apparatus according to claim 1 further comprising conveyor means for transferring heated workpieces continuously along said furnace hearth at a spaced relation from said panels.
 3. An apparatus according to claim 2 wherein at least two of said panelS are supported by said means for rotatably supporting in an edge-to-edge relationship along the length of the cooling furnace.
 4. An apparatus according to claim 3 wherein a pair of said panels is supported by said means for rotatably supporting to extend in an end-to-end relationship across the width of said cooling furnace.
 5. An apparatus according to claim 4 wherein said means for rotatably supporting said panels includes a plate member projecting from the roof of said furnace for rotatably supporting adjacent ends of said panels while arranged in said end-to-end relationship.
 6. An apparatus according to claim 1 further comprising temperature measuring means for workpieces supported on said furnace hearth, and control means responsive to said temperature measuring means for energizing said drive means.
 7. An apparatus according to claim 1 wherein said fluid coolant means includes longitudinal ducts arranged at spaced intervals across the width of each panel.
 8. An apparatus according to claim 7 wherein said insulation means is further defined to include a fibrous mat of heat insulating material having a working temperature range up to 2200*F. 